Refactor the UpdateEngine and its actions in the component updater.

components/update_client/action_update_check.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef COMPONENTS_UPDATE_CLIENT_ACTION_UPDATE_CHECK_H_
-#define COMPONENTS_UPDATE_CLIENT_ACTION_UPDATE_CHECK_H_
-
-#include <map>
-#include <memory>
-#include <string>
-#include <vector>
-
-#include "base/macros.h"
-#include "base/threading/thread_checker.h"
-#include "base/version.h"
-#include "components/update_client/action.h"
-#include "components/update_client/crx_update_item.h"
-#include "components/update_client/update_client.h"
-#include "components/update_client/update_engine.h"
-#include "components/update_client/update_response.h"
-#include "url/gurl.h"
-
-namespace update_client {
-
-class UpdateChecker;
-
-// Implements an update check for the CRXs in an update context.
-class ActionUpdateCheck : public Action, private ActionImpl {
- public:
-  ActionUpdateCheck(std::unique_ptr<UpdateChecker> update_checker,
-                    const base::Version& browser_version,
-                    const std::string& extra_request_parameters);
-
-  ~ActionUpdateCheck() override;
-
-  void Run(UpdateContext* update_context, Callback callback) override;
-
- private:
-  void UpdateCheckComplete(int error,
-                           const UpdateResponse::Results& results,
-                           int retry_after_sec);
-  void OnUpdateCheckSucceeded(const UpdateResponse::Results& results);
-  void OnUpdateCheckFailed(int error);
-
-  void HandleUpdateCheckOK(const UpdateResponse::Result& result,
-                           CrxUpdateItem* crx);
-  void HandleUpdateCheckNoupdate(const UpdateResponse::Result& result,
-                                 CrxUpdateItem* crx);
-  void HandleUpdateCheckError(const UpdateResponse::Result& result,
-                              CrxUpdateItem* crx);
-
-  std::unique_ptr<UpdateChecker> update_checker_;
-  const base::Version browser_version_;
-  const std::string extra_request_parameters_;
-
-  DISALLOW_COPY_AND_ASSIGN(ActionUpdateCheck);
-};
-
-}  // namespace update_client
-
-#endif  // COMPONENTS_UPDATE_CLIENT_ACTION_UPDATE_CHECK_H_